Title: An ultrafilter proof of the 2-dimensional Halpern-Laüchli Theorem

Abstract:

We will discuss the Halpern-Laüchli Theorem and provide a new proof in dimension 2. The idea is to use an ultrafilter on ω to turn combinatorics on trees into combinatorics on the branches, that is Cantor space. Time permitting, we will discuss obstacles to generalizing the proof to higher dimensions.